This invention relates to a booth in which an automobile or other article can be spray painted and thereafter heat cured with complete safety and in accordance with governmental and industry codes and regulations.
Large scale spray painting operations for automobiles or the like commonly have elongated subdivided tunnels through which a vehicle is moved for various stages of painting and curing. In an initial portion of the tunnel the vehicle is spray painted using conventional compressed air paint spraying equipment. During spray painting air is drawn past the vehicle for removing overspray and solvent fumes. This air is filtered and may be scrubbed to remove solvents before being discharged.
When the spraying is completed, the vehicle is then moved into another portion of the tunnel where the painted surfaces are heated to around 170.degree. F. for rapidly curing the paint. Although paint may dry to the touch in a reasonable time at ambient temperature, it does not cure to full hardness for a period of forty-eight hours to as much as sixty days, depending on the type of primer, lacquer, enamel or the like that is used. Heat curing on the other hand can usually be achieved in twenty to forty minutes. It is therefore highly desirable to heat cure paint on a broad variety of articles, including automobiles.
The sophistication and expense of a spray painting and curing tunnel precludes its use by many small automotive shops that may paint only two or three or fewer cars per day. Such shops have used a variety of makeshift arrangements for painting and curing automobiles.
It is generally required by regulation that painting be in a booth for minimizing environmental contamination. Even in the absence of regulation, painting booths are commonly used so that filtered air passes over the vehicle to minimize imperfections due to dust. After painting, the vehicle may be moved to another area where banks of heat lamps or quartz tube infrared heaters are arrayed for heating the vehicle. Such arrangements make it difficult to obtain uniform heating and may require substantial space.
In other shops portable heat lamps or the like are moved into the spray paint booth after spraying is completed and the vehicle is cured in the booth. Again, uniformity of heating is difficult and subject to the skill of the operator placing the heaters. In either of these arrangements there is the possibility of damaging the uncured paint as the vehicle or heaters are moved.
There has not previously been any booth having permanently installed heaters in which spray painting operations could also be conducted. Because of the high flammability of paint fumes, permanently installed heaters have been impractical for safety reasons. Heating cannot commence until paint fumes are safely removed. Further, it has not been feasible to place heaters in the spray booth during spraying since accumulations of overspray on such heaters can also be a substantial safety hazard.
It is therefore desirable to provide a booth in which vehicles or the like can be spray painted and thereafter cured in the same booth with permanently installed heaters without introducing flammability safety problems.